//通过元素ID访问
var objById =document.getElementById("province");
console.log(typeof objById);
console.log(objById);
//通过标签访问
var objByTagName =document.getElementsByTagName("li");
console.log(typeof objByTagName);
for (var i=0;i<objByTagName.length;i++){
    console.log(objByTagName[i]);
}
//通过类访问
var objByClassName =document.getElementsByClassName("cur");
console.log(typeof objByClassName);
for (var i=0;i<objByClassName.length;i++){
    console.log(objByClassName[i]);
}
//遍历元素节点
function  traversal(node) {
    //node为元素节点
    if(node && node.nodeType==1){
        console.log(node.nodeName);

    }
    //子节点
    var childNodes =node.childNodes;
    for(var i=0;i<childNodes.length;i++){
        var item=childNodes[i];
        if(item.nodeType==1){
            traversal(item);
        }
    }

}
traversal(document.documentElement);
//属性节点
var objp =document.getElementsByTagName("p");
for(var i=0;i<objp.length;i++){
    var  txtTitle =objp[i].getAttribute("title");
    console.log(txtTitle);
}
document.getElementById("province").setAttribute("title","省份列表");
